12.07.2008

Why did the Roman Empire fall? This question is in the headlines today.

Portrait of Edward Gibbon in 1779

Edward Gibbon, an observer from the age of reason and a close confidante of Lord North, the British prime minister charged with the prosecution of the war against the rebellious American colonies, argued first that the division of the empire, followed by religious revolution, was responsible:

"The clergy successfully preached the doctrines of patience and pusillanimity; the active virtues of society were discouraged; and the last remains of the military spirit were buried in the cloister; a large portion of public and private wealth was consecrated to the specious demands of charity and devotion; and the soldiers' pay was lavished on the useless multitudes of both sexes, who could only plead the merits of abstinence and chastity. Faith, zeal, curiosity, and the more earthly passions of malice and ambition kindled the flame of theological discord; the church, and even the state, were distracted by religious factions, whose conflicts were sometimes bloody, and always implacable; the attention of the emperors was diverted from camps to synods"

However, modern historians debate at least a dozen causal theories, with differering patterns of emphasis.

Climate change, indicated by samples taken from a cave near Jerusalem, adds a key scientific wrinkle to the debate, as it seems that between 100 and 700 C.E., the Mediterranean experienced an exceptionally dry climate, with driest periods occurring around 100 and 400 C.E.

Recent research has materially linked the decline of the North African provinces west of Egypt to the fall of the western half of the empire, as archaeology and aerial geographical analysis now hint at vast areas under cultivation which began to decline around the year 400. The size and extent of agriculture, large-scale shipping and transport monopolies, and the links between these enterprises and the Roman treasury are only now becoming understood. When archaeologists first looked at the region, they found large, well-preserved cities such as Thamugadi seemingly in the middle of the desert, reclaimed by the Sahara, but underestimated the productivity of the region, which had a year-round growing season, unlike Europe.

New estimates suggest that these provinces contributed 1/3 to 1/2 of the tax revenue of the empire and this mercantile system based in Africa, but linking East and West, North and South by sea formed the basis for Imperial wealth in an era when tribute and spoils from war had declined; the last profit-taking wars being principally the removal of accumulated wealth from the Temple during the sack of Jerusalem in the Jewish revolt which was in fact a Roman province and not an external enemy (A.D. 66-73), and the destruction of the Parthian capital Ctesiphon in 198 A.D.

The African provinces depended upon a delicate balance of water resources and increasing demand. Long-term drought presumably caused a perennial decrease in the productivity of the extensive irrigation works, pulling the plug on the empire's sustaining financial lifeblood just as defensive wars and a governmental expansion required heavy and unremitting expenditures.

Bronze, silver-washed antoninianus of Probus, 276-282 C.E.

While the emperors attempted to bail themselves out with massive debasement programs, issuing billions of coins of low quality, such measures did not right the ship of state. The eastern half of the Empire survived longer because of its pre-existing greater wealth, re-organization which accessed new powers of longevity, and greater level of urbanization. Gold coin of Anastasius, Eastern Roman emperor, 491-518 C.E.

Unlike in the west, where the German warlord Odoacer replaced the nominal emperor Romulus Augustus in 476; in the East, Anastasius (491-518) reformed the economy and tax codes, leaving the treasury with a surplus of 320,000 pounds of gold upon his death in 518.